Rabies vaccination at a virus-inoculated site as an alternative option to rabies immunoglobulin

Rabies: Presentation, case management and therapy

Several Lyssaviruses are known to be a causative agent of rabies and rabies like syndrome. There are no proven effective treatment strategies for symptomatic rabies patient. Risk of infection from dog variant of rabies virus is highest with deep bite reaching muscular layer and much higher when compared to scratch. Failure of viral eradication at the central nervous system (CNS) is partly due to inadequate immune response. Favipiravir selectively inhibit viral RNA polymerase and has been shown to reduce rabies replication in neuronal cell and mouse model system. Endocannabinoid system has emerged as an important regulator for CNS integrity, cell fate and may serve as an important novel neuroprotective agent. Cannabinoid may be able to regulate the impaired homeostasis induced by rabies virus by promoting infected cell survival and promote complete autophagy in infected cell.

Benefit-cost analysis of the policy of mandatory annual rabies vaccination of domestic dogs in rabies-free Japan

Japan is one of the few rabies-free countries/territories which implement the policy of mandatory vaccination of domestic dogs. In order to assess the economic efficiency of such policy in reducing the economic burden of a future canine rabies outbreak in Japan, a benefit-cost analysis (BCA) was performed using probabilistic decision tree modelling. Input data derived from simulation results of published mathematical model, field investigation conducted by the authors at prefectural governments, literature review, international or Japanese database and empirical data of rabies outbreaks in other countries/territories. The current study revealed that the annual costs of implementing the current vaccination policy would be US$160,472,075 (90% prediction interval [PI]: $149,268,935-171,669,974). The economic burden of a potential single canine rabies outbreak in Japan were estimated to be US$1,682,707 (90% PI: $1,180,289-2,249,283) under the current vaccination policy, while it would be US$5,019,093 (90% PI: $3,986,882-6,133,687) under hypothetical abolition of vaccination policy, which is 3-fold higher. Under a damage-avoided approach, the annual benefits of implementing the current vaccination policy in expected value were estimated to be US$85.75 (90% PI: $55.73-116.89). The benefit-cost ratio (BCR) was estimated to be 5.35 X 10(-7) (90% PI: 3.46 X 10(-7)-7.37 X 10(-7)), indicating that the implementation of the current policy is very economically inefficient for the purpose of reducing the economic burden of a potential canine rabies outbreak. In worse-case scenario analysis, the BCR would become above 1 (indicating economic efficiency) if the risk of rabies introduction increased to 0.04 corresponding to a level of risk where rabies would enter Japan in 26 years while the economic burden of a rabies outbreak under the abolition of vaccination policy increased to $7.53 billion. Best-case analysis further revealed that under relatively extreme circumstances the economic efficiency of the current policy could be improved by decreasing the vaccination price charged to dog owners, relaxing the frequency of vaccination to every two to three years and implementing the policy on a smaller scale, e.g. only in targeted prefectures instead of the whole Japan.

Lyssaviruses and rabies: current conundrums, concerns, contradictions and controversies

Lyssaviruses are bullet-shaped, single-stranded, negative-sense RNA viruses and the causative agents of the ancient zoonosis rabies. Africa is the likely home to the ancestors of taxa residing within the Genus Lyssavirus, Family Rhabdoviridae. Diverse lyssaviruses are envisioned as co-evolving with bats, as the ultimate reservoirs, over seemingly millions of years. In terms of relative distribution, overt abundance, and resulting progeny, rabies virus is the most successful lyssavirus species today, but for unknown reasons. All mammals are believed to be susceptible to rabies virus infection. Besides reservoirs among the Chiroptera, meso-carnivores also serve as major historical hosts and are represented among the canids, raccoons, skunks, mongooses, and ferret badgers.  Perpetuating as a disease of nature with the mammalian central nervous system as niche, host breadth alone precludes any candidacy for true eradication. Despite having the highest case fatality of any infectious disease and a burden in excess of or comparative to other major zoonoses, rabies remains neglected. Once illness appears, no treatment is proven to prevent death. Paradoxically, vaccines were developed more than a century ago, but the clear majority of human cases are unvaccinated. Tens of millions of people are exposed to suspect rabid animals and tens of thousands succumb annually, primarily children in developing countries, where canine rabies is enzootic. Rather than culling animal populations, one of the most cost-effective strategies to curbing human fatalities is the mass vaccination of dogs. Building on considerable progress to date, several complementary actions are needed in the near future, including a more harmonized approach to viral taxonomy, enhanced de-centralized laboratory-based surveillance, focal pathogen discovery and characterization, applied pathobiological research for therapeutics, improved estimates of canine populations at risk, actual production of required vaccines and related biologics, strategies to maximize prevention but minimize unnecessary human prophylaxis, and a long-term, realistic plan for sustained global program support to achieve success in disease control, prevention, and elimination.